Automatic stop mechanism for power hoists



aflxfpril52s, 1925. Z 1,535,692

, W E. SIMPSON I I AUTOMATIC MECHANISM FOR POWER HOIS'I'S Fil ed Dec.19, 1919 zsm ts-sheet 1 Patented A zs, 1925.

. UNITED STATES PATENT orrics;

WILLIAM E. snvrrson, or DETROIT, MIC IGAN, ASSIGNOR TO PALMERJBEECOMPANY,

T DETROIT, MICHIGAN, A CORPORATION or MICHIGAN.

AUTOMATIC STOP MECHANISM FOR POWER HOISTS.

Application filed December 19, 1919. Serial No. 345,976;

i To all coho m, it may concern i Be it known that I, VILLIAM E.SIMPSON, asubject of the King of Great Britain and Ireland, residing atDetroit, in the county of Tayne and State of Michigan, have inventedcertain new and useful Improve-f ments .111 Automatic Stop Mechanlsm fortion further consists in the construction of a stop mechanisinunit whichis attachable to a hoist unit unprovided with such mechanism, andfurther in various features of construction as hereinafter set forth.

In the drawings: i

Figure 1 is a central longitudinal section through a manual operablehoist;

. F gure 2 1s a similar view through the construction converted intov apower hoist and provided with my improved stop mech*.

anism.

Figures .3, 4 and 5 are sectional views taken onthe lines 33, 44; and55, respectively, of Fig. 2.

As shownin Figure 1, A is ahousing for enclosing the hoist mechanism; Bis a sw1veled hook formlng a support for said hous mg; C is a chainwheel for manual operation; D is a shaft on which said chain wheel ismounted extending axially through the housing A. E is a driven chainwheel sleeved upon the shaft D and provided with load-supporting rollerbearings F. G is a pinion on the shaft D in mesh with plan- 'etarypinions H engaging an annular internal gear rack Iupon the housing, andJ are journal pins for said planetary gear wheels which are carried by ahead K mounted on a sleeve extension L of the driven wheel E.

The construction above described is designed for manual operation, butis adapted for attachment of a power unitthereto. To this end thehousing A is provided with a inoved, permits of registering with saidhousing an auxiliary houslng N contalnlng a motor unit 0 and astep-downtransm1s sion gearing P. for coupling the same with the shaft D. When soequipped, the hoist canbepower operated but there is danger that acareless operator might run the motor beyond the hoisting limit withdisastrous results. a c To apply my step mechanism to the construction,the peripheral port-ion G :of the operating wheel C is removed bydisengagement of the attachment screws C An auxiliary housing Q, maythen be attached to the? end of the housing A, said auxiliary housingenclosing the stop mechanism. This mechanism comprises a rotary shaft Rwhich is screw-threaded for engagement with a pinion S, said pinionbeing in mesh with a long tooth gear wheel T mounted on a shaft U. Thepinion 'S has a limited freedom for longitudinal movement on the shaft Rwhenthe latter is revolved, but at opposite ends are arranged stops Vand V which prevent further movement and cause the locking of the pinionrotatively to the shaft. The shaft R. is revolved from the shaft D bymeans of the gears D and R upon the shafts D, and B respectively, thegears D being substituted for the washer D in the manually operatedhoist. The gear wheel T has its teeth of sufl'icient length to remain inlocked rotatively to the shaft, further rotation. thereof will cause thetransmission of rotary movement to the gear whee]. T. The gear wheel Tis yieldably held in a neutral position by resilient means, such as thespiral spring W, which as shown is arranged within a recess in the gearand has one end connected to the gear and its opposite end connected toa stationary stop X, so that whenever the pinion S is free to revolve,the gear wheel will be returned to its neutral position. Secured to theshaft U is a switch arm U forming an element of a circuit closer andrheostat ofany suitable construction for controlling the motor 0, and Uis an operating arm attached to the shaft U and adapted to be manuallyactuated to control the operation of the motor.

Vithin the housing Q, are also arranged fuses Y and other accessories ofthe electric control and said housing is preferably formed in sectionshinged to each other at Q and normally locked by a bolt Q Thearrangement is such that by unfastening the bolt Q} the housing Q may beopened to provide access to the switch.

In changing the hoist from a manually operable construction to the poweractuated and automatically stopped construction the operator firstremoves the cover hi and places in position the housing N, as has beenpreviously described. He also disengages the peripheral portion C of theoperating wheel C, which permits of engaging the housing Q with the stopmechanism arranged therein. hen thus changed, the hoist is power drivenand is both manually and automatically controlled.

\Vhat I claim as my invention is:

1. A stop mechanism for hoists, comprising a controlling switch,mechanism for throwing said switch including a driven gear wheel, adriving gear wheel in mesh with and having its axis parallel to that ofsaid driven gear wheel said driving gear wheel being longitudinallyslidable in mesh with said driven gear wheel, a screw threaded shaft onwhich said driving gear wheel is mounted for causing the longitudinalmovement thereof upon the rotation of said shaft, and a stop forlimiting the longitudinal movement of saiddriving gear wheel upon saidshaft to cause the rotation of said driving gear wheel with the shaftand the rotation of said driven gear wheel and the actuation of saidswitch.

2. A stop mechanism for hoists, comprising a controlling switch,mechanism for operating said switch including a shaft connected to saidswitch, a driven gear wheel connected to said shaft, a driving gearwheel longitudinally slidable in mesh with said driven gear wheel, ascrew threaded shaft having its axis parallel to that of saidfirstmentioned shaft and on which said driving gear wheel is mounted,said screw threaded shaft being adapted to cause the longitudinal travelof said driving gear wheel upon rota tion of said screw threaded shaft,a stop arresting longitudinal travel of said driving gear wheel uponsaid screw threaded shaft to cause the rotary movement of said drivinggear wheel, and the rotary movement of said driven gear wheel, andmechanism driven from the hoist for rotating said screw threaded shaft.

8. A stop mechanism for hoists comprising an electric switch, aresilient yieldable connection for throwing said switch, a longtoothedgear wheel to which one end of said resilient yieldable connection isattached, a pinion in mesh with and having its axis parallel to that ofsaid long-toothed gear wheel, a screw-threaded shaft on which saidpinion is mounted, the rotation of said shaft causing the longitudinaltravel of said pinion thereon while in mesh with said longtoothed gear,a stop for limiting the longitudinal movement of said pinion to causethe rotation of the same with said shaft, and mechanism driven from thehoist for actuating said screw-threaded shaft.

l. A stop mechanism for hoists, comprising an electric switch, aresilient connection for normally maintaining said switch in neutralposition, a long toothed gear wheel within which said resilientconnection extends and to which one end of said resilient connection isattached, a pinion in mesh with said long-toothed gear wheel, a screwthreaded shaft on which said pinion is mounted, the rotation of saidshaft causing the longitudinal travel of said pinion thereon, while inmesh with saidlong-toothed gearwheel, a stop upon said screw-threadedshaft for limiting the longitudinal movement of said pinion to cause therotation of the same with said shaft, and mechanism driven from thehoist for actuating'said screw-threaded shaft.

In testimony whereof I affix my signature.

WILLIAM E. SIMPSON.

